BACILLUS AVISEPTICUS 223 



passage of the bacteria through the bodies of susceptible animals 

 increases its virulency, and exposure to air and light lessens it. 



Natural Infection. Among fowl, infection is, as a rule, transmitted 

 through the gastro-intestinal tract. It has been ascertained that 

 fowls contract the disease from eating infected organs and food soiled 

 with feces from infected birds. The bacteria, after ingestion, invade 

 first the lacteals, then the lymph clefts, and from them the blood 

 current. It is also highly probable that ectogenous parasites (lice) 

 can spread the disease from sick to healthy birds. 



Resistance. In moist soil protected against air and light the Bacil- 

 lus -avisepticus can remain alive and virulent for a considerable time; 

 in manure, according to Gartner, at least one month; in putrefying 

 cadavers, according to Kitt, three months. It is not killed by freezing, 

 but it soon perishes when dried out. It loses its virulency, according 

 to Kitt, when exposed in the moist condition for one-half hour to 

 45 to 46 C.; it is killed at from 80 to 90 C. in five to ten minutes. 

 Solomon and others have studied the effects of disinfectants upon the 

 bacillus, and have found that chlorinated lime in a dilution of 1 to 

 100; slacked lime, 1 to 20; sulphuric acid, 1 to 300; hydrochloric 

 acid, 1 to 500, and 1 per cent, carbolic acid rapidly kill the organism. 

 Repeated whitewashing of infected places is an excellent means of 

 disinfection, but before application the woodwork should be washed 

 with hot soda solution and the floors scrubbed with creolin or lysol 

 solution. Sick animals must be separated from the healthy, and 

 cadavers should be deeply buried, or, better still, burned. According 

 to the observation of several investigators the bacilli are frequently 

 found as saprophytes in the outside world. 



Immunization. The first experiments in protective inoculation 

 against this bacillus by attenuated cultures were made by Pasteur. 

 Attenuated cultures powerful enough to kill pigeons will only cause 

 local necrotic processes in chickens, geese, and ducks. Passive immu- 

 nization has been practised (Kitt) with a serum from horses hyper- 

 immunized against the Bacillus avisepticus. Jensen has observed 

 that chickens which have passed through an infection with the bacillus 

 of the hemorrhagic septicemia of calves were subsequently immune 

 against infection with the Bacillus avisepticus. The latter, it has 

 been claimed, produces a soluble toxin which will pass a Pasteur filter. 

 Since it is known, however, that very" small bacilli sometimes pass 

 through a Berkefeld filter, it is possible that the transitory effects of 

 the filtrate depended upon the presence of a very few not very virulent 

 bacilli. 



Other Septicemias among Birds. In addition to the common fowl 

 cholera a number of other septicemias in birds have been described. 

 They are evidently not identical with the avisepticus infection, and 

 are caused by different organisms. Some of these affections are: 



A disease observed among pigeons in New Jersey by Moore; one 

 observed among chickens by Noergaard and Mohler, caused by a 



